Take, for example, just like I am coming from Boston here by aeroplane. It is very nice discovery. But as soon as you get on the aeroplane, every second there is danger—because there is no guarantee. There is no guarantee. So similarly, we may crossing over the street... Oh, there is danger. Recently in Delhi one of our Godnephew, oh, he was crushed by motor accident, completely crushed. He fell down, and the motor car passed over him, and all the bones were crushed. I have received that letter. So we should know that this place is not at all safe. At any moment there is danger. Padaṁ padaṁ yad vipadām. Therefore in the Cāṇakya Paṇḍita's version it is said that "If you want to have spiritual realization, then you should always think that 'Death is coming, and danger is coming immediately.' " That should be our attitude.
And in the Bhagavad-gītā it is also said that those who are intelligent persons, those who are making progress to become wiser, for them four things should be kept always in view. What is that? Janma-mṛtyu-jarā-vyādhi-duḥkha-dosanudarśanam (BG 13.9).